1. Field of the Invention
The present invention relates to an inkjet recording method and an inkjet recording device.
2. Description of the Related Art
Use of an inkjet recording method has been recently rapidly increased, as a color image is easily recorded, and running cost is low. However, this method has problems that an image defect tends to occur depending on a combination of an ink and a recording medium for use, and image quality is significantly reduced.
When coated paper using filler (e.g., calcium carbonate, and kaolin) as a coating layer material, such as a commercial printing or publication printing coated paper is used as a recording medium, for example, an image may be significantly blurred, or density of the image may not be appeared. This is because the coated paper is not designed to absorb a large amount of the ink within a short period of time, unlike inkjet paper, and therefore absorption of the ink is not sufficient and hence causing blurring, or even when the ink is penetrated into a coating layer, the colorant of the ink is sealed with the filler having high sealing properties, such as kaolin, in the coating layer. Accordingly, it has been considered that this type of paper is not suitable for inkjet recording at all.
Meanwhile, as for an inkjet ink, an aqueous pigment ink, in which a pigment is turned into fine particles and dispersed in water, has been attracted attention. As a pigment has a similar composition to that of a colorant used in a typical commercial printing ink, use of such ink is expected to achieve a print which is similar to that of commercial printing. When recording is performed on a commercial printing or publication printing coated paper using the pigment ink, however, there are the following problems. Specifically, an image is blurred as absorption of an ink is insufficient, the pigment is not fixed at all after drying the ink, and sufficient glossiness cannot be achieved.
Therefore, disclosed is a recording method using a pigment ink having high permeability and a recording medium having low absorption (see Japanese Patent Application Laid-Open (JP-A) No. 2007-144975).
Moreover, disclosed is use of a heat roller as a drying auxiliary unit in order to improve drying or fixing ability on a printed surface just after printing (see Japanese Patent (JP-B) No. 2860123).
Furthermore, disclosed is to provide a protective layer with a UV varnish in order to protect a surface of paper abrasion resistance of which is reduced by pigment residues (see JP-A No. 2004-330568).
In the case where commercial printing or publication printing is performed, it is often necessary to output several hundreds to several thousands prints at once. Therefore, a printer for use needs to continuously and stably produce an image without causing any image defect. If an inkjet printer is used for this use, a problem is particularly clocking or nozzle due to drying of an ink, or formation of lines in an image due to an obscured ejection angle by the dried ink adhered around the nozzle. The most effect method for preventing this problem is to add a water-soluble organic solvent having a high boiling point to an ink to prevent drying of the ink.
The method disclosed in JP-A No. 2007-144975, however, has a problem that it takes to a long time for the ink to become a state, where the ink is not blurred even with abrasion (fixed state), if a recording medium having extremely low ink absorption, such as a commercial printing sheet, is combined with an ink containing a water-soluble organic solvent having a high boiling point, which has a high effect of preventing drying of a printer head (clogging of a nozzle). When inkjet recording for commercial printing is performed in accordance with the method disclosed in JP-A No. 2007-144975, therefore, it takes a long time for fixing, and it cannot be used if it is desired to send out the prints, as flyers or catalogs, just after the printing.
The method disclosed in JP-B No. 2860123 uses a solvent ink containing aliphatic hydrocarbon as a main component, and therefore there is a problem that a large load is provided to the environment, as a volatile organic compound is released by heating.
In accordance with the method disclosed in JP-A No. 2004-330568, moreover, a heating unit is necessary for image formation, and the UV varnish needs to be cured by a UV lamp after ejecting the UV varnish on an entire surface of a paper medium by a post-processing unit. Therefore, there is a problem that a device for use is complicated, as well as a large load is provided to the environment.